Air film supported and guided load support member

ABSTRACT

A fluid levitated generally convex support member particularly useful in supporting a pallet, plate or belt such that the pallet, plate or belt load may be moved in an air powered track system, the system including at least one concave track with means for supporting and guiding the convex member and the pallet, plate or belt thereabove on a thin film of pressurized air jetting from nozzles in the track. The support member includes a generally tubular, flexible and partly deformable outer member and means for internally stressing the outer member so that under load there will be controlled deformation thereof. The deformed member will be closely complementary to the track surface to maximize load carrying capacity while minimizing fluid support power requirements and the detrimental effect of track deformities. Of particular significance is the ability of the support assembly covering to vibrate at high frequency at the track surface in response to the track jets and the wedge flow of the fluid support film to provide a pumping action which propagates and augments the pressure of the support film. Also, the small air film provides a controlled air gap which permits the use of electromagnetic propulsion means installed as part of the track for reaction with suitable secondary devices included in the support member. Under load removal there will be controlled recovery of the shape of the outer member. The support member exhibits excellent wear, cleanliness, cushioning, manufacturing, and select frequency response and damping characteristics.

The present invention relates in general to supports for articles movingon a conveyor and in particular to pallets, skids or plates and supportstherefor.

BACKGROUND OF THE INVENTION

In Canadian Pat. No. 950,853 issued July 9, 1974 and assigned to acommon assignee, an air conveyor was described and claimed, oneembodiment of the conveyor utilizing a concave, trough-like track with aplurality of nozzles therein. The nozzles were asymmetrically positionedparallel to the center-line of the track and were directed at an angleto the center-line with respect to a tangent at the track surface. Whenan article to be conveyed, such as a roll of toilet tissue or a roll orpaper towelling, was placed in the track and subjected to high velocityair flowing from the nozzles the article was displaced from a restposition coaxial with the track to a position slightly to one side ofthe center-line and was supported on the thin film of the issuing airwhich adhered to the curved track surface. In effect, the supporting airfilm formed a wedge of supporting fluid between the concave surface ofthe track and the convex surface of the supported article. The stabilityof this system has proven to be extremely good and the power requirementhas proven to be very small.

Another Canadian patent (No. 1,002,565 issued Dec. 28, 1976 to the sameinventor as in the previously identified patent) disclosed and claimedan up-scale version of the basic conveyor system, that invention being avehicular transportation system using either one or two parallel tracksand a vehicle having appropriate mating support surfaces for support inor on the track(s).

In the first-identified patent mention was made of a conveyor systemutilizing tracks laid in the floor of a factory with the supportedarticle being a plate arrangement having a lower surface complementaryto the track whereby commodities to be handled in the factory would bepositioned on the uppermost surface of the plate and moved along thetrack in the factory floor to a new location, such as the loading dock.This concept is basic to a warehousing system and can be extended evenbeyond the warehouse to transport trailers, rail cars and aircraft thatmight carry the merchandise from the factory or warehouse to thedistributor or to the eventual consumer.

This extension of the basic conveyor concept from the situation wherethe article positioned in the track is the actual product to thesituation where the article positioned in the track supports the actualproduct requires considerations not previously deliberated upon in greatdetail. The product support could be a pallet or even a belt adapted toride in the track. For example the question of stability suggests that atwo-track conveyor is desirable for a pallet, as does the question ofvery heavy loads, weight distribution and power requirements toestablish lift. A single track would be satisfactory for supporting abelt. Also durability and flexibility of the track and support should beconsidered as should the question of cushioning when the product isfragile.

The question of load shocks and cyclical or variable track supportforces becomes more paramount when the concept of a warehouse converyoror distribution system is extended to the common carriers such astransport trailers. In many instances it would be desirable for a load,moving on an air supported pallet in the warehouse, to remain on thepallet and to pass directly, without the need of a fork-lift truck, intoa waiting carrier. Once inside the carrier the pallet would rest on itssupports which in turn would be restrained within the conveyor trackwith the air turned off. This situation makes it very desirable toisolate the cargo or load from the carrier body as much as possible,preferably through the cushioned pallet supports.

SUMMARY OF THE INVENTION

The present invention is intended to provide a pallet or belt supportwhich can be utilized with an air conveyor such as that described inCanadian Pat. No. 950,853 and which will meet the requirements of load,cushioning, wear and economy dictated by a competitive and demandingindustry.

Considerable experimentation with the durability and efficiency ofprototype conveyor systems and load supporting arrangements has shownthat it is possible to achieve the support of high loads at low powerratings with configurations that have been subjected to pallet loads of3600 lbs. while being flexed at near resonant frequency (8cps) through1.5 million cycles at -51° without encountering any apparent incipientfailure or deterioration. Such supports have also levitated a standardpallet load of 4 tons on a 60% open 10 foot track at a track horse powerrating of only 1.8 hp. (equates to a track pressure of 32 psig.) A loadof 2 tons on the other hand only requires about 0.5 hp. or a pressure ofonly 14 psig. on a 60% open 10 foot experimental track made from astandard pipe sector.

The above results were achieved with a pair of cylindrical (oblong)supports, each about 48 inches long and about 21/4 inches in height.Each was supported in a track of 6 inch radius having a few nozzles perfoot of track, the nozzles being 0.030 inches in diameter and angled at45 degrees to the track length and at 20 degrees to the track surface.Any internal nozzle clogging is precluded by low air mass flows and theupward direction of the flow thereof while high air velocities of thenozzle exit clear the outer portion of the nozzle and track. Eachsupport in the test included an outer flexible yet strong coveringformed of ultra high density polyethylene, a central spiral-wounddeformable core made of a flexible, semi-rigid material such aspaperboard, and between the covering and the core a light weightresilient material capable of compaction under load and recovery orrebound upon load removal. In fact, the core and resilient material usedin the test were taken from a longer roll of uncut and unperforatedcreped paper tissue product.

A variation of the above invention is the use of a substitute supportmember of extended length comprising a relatively large diameter innercore of deformable material which could include wire mesh, wire loops ormetal sheet with an outer resilient covering over a thin layer ofcompliant filler to form a reinforced flexible conveyor belt member tofit the concave air track section when compressed to a curved thinsection under loading. This belt can be joined to form a continuous loopbelt conveyor levitated on a thin film of supporting air and guided bythe concave air track jet system. The belt can support various types ofconveyed material loaded on its uppermost concave surface. The lowersurface of the belt conforms with the curved track surface and can bemade to vibrate in conjunction with the track air jet flows to propagateand augment the air film support. In this manner a conveyor belt with norollers or idlers can convey various materials or loads with minimalfriction, power and maintenance.

When the metal (collapsed) inner core is utilized as a secondary elementfor a linear elecromagnetic propulsion primary device included in thesupport track, the film supported belt forms a self-driven conveyorsystem of unique length and load carrying capabilities. The linearelectromagnetic propulsion coils can be distributed over the entirelength of the supporting fluid track, spaced to provide additionalpropulsion as required at various grade changes, even to brake or retardthe belt load speed on downgrades as required by use of suitable motorcharacteristics. The absence of idlers, the use of a small belt section(due to drive distribution), and the use of one moving part with nolubrication make this type of conveyor especially useful in longdistance conveying of say ore or chips with minimal power requirementsand cost.

A similar construction utilizing metallic elements as the secondary fora linear electromagnetic propulsion primary device in the support trackcan be included in a pallet or plate support member as well.

Broadly speaking, therefore the present invention may be characterizedas a load supporting means for positioning between a load and a loadsupporting surface, the means being capable of supporting the load andof substantially isolating the load from forces influencing the positionof the supporting surface, the means comprising a generally tubularouter member formed of a flexible, partly deformable material and,internally of the member, means for peripherally prestressing themember.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic cross-section of a conveyor system, similar tothat of Canadian Pat. No. 950,853, illustrating the principle ofsupport.

FIG. 2 shows an end view of a support in a track and under load.

FIG. 3 shows the support of FIG. 2 with the load removed.

FIG. 4 shows a perspective view of a support shoe cover after moulding.

FIG. 4a shows a perspective view of a support shoe cover followingremoval of an end cap, insertion of a roll and replacement of the endcap.

FIG. 5 shows a cross-section of the support shoe taken along the line5--5 of FIG. 4a.

FIGS. 6A, 6B, and 6C, show cross-section of sample rolls illustratingthe value of a core.

FIG. 7 shows a force diagram of the shoe.

FIGS. 8 to 12 show alternate ways of internally loading a support shoe,with FIG. 11 suggesting a means of varying the support shoe prestressingwith variable loading.

FIG. 13 shows a perspective view of a modular moldable pallet.

FIG. 14 shows an end view of the pallet of FIG. 13 and

FIG. 15 shows a section along the line 15--15 of FIG. 13.

FIG. 16 shows a transverse section of another embodiment of the presentinvention, with a load in place (same sheet as FIG. 1).

FIG. 16a shows a transverse section of the other embodiment before,during and after load application (same sheet as FIG. 1).

FIG. 17 shows an example of a conveyor system utilizing the otherembodiment of the invention (same sheet as FIG. 1).

FIG. 18 is a schematic representation in partial cross-section of thepresent invention showing certain alternative constructions, each ofwhich may be independent of or combined with other features of theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Before describing the present invention in detail it is deemedadvantageous to breifly discuss the principle of operation of a supportsystem utilizing the present invention. This will be accomplished withreference to FIG. 1 which is a schematic, rather than detailed,representation of the support system.

Having regard to FIG. 1 it is seen that in its basic form a conveyorsystem may include a generally concave trough 20 which is intended tosupport a generally convex article 22. This article may be a cylindricalobject intended to be transferred along the conveyor, it may be a beltas hereinafter described, or it may be a portion of a larger object,such as a pallet or skid. In the last case it is likely that a secondconveyor or trough will be positioned beside and parallel to trough 20and that the pallet will be supported by two articles 22, one for eachtrough 20.

Below the trough 20 is a plenum chamber 24 defined by plenum wall 26.Chamber 24 is provided with pressurized fluid such as air, at an optimumpredetermined pressure. Sets of nozzles 28 and 30 are longitudinally andtransversely spaced in the trough to communicate the plenum chamber 24with the atmosphere. Jets 28 and 30 may be angled relative to thetrough, it being noted that the sets of nozzles 28 and 30 may beasymmetrically positioned on opposite sides of the trough longitudinalcenter-line, a configuration which permits early generation of a fluidfilm support cushion and a generation of a pulsating pressure wave, tobe hereinafter discussed.

The high velocity angled jets exiting from nozzles 28 and 30 of theconcave surface in reaction with the proximity of the article 22 createa wedge-like film of pressurized fluid in the gap g formed between thearticle 22 and the track supporting surface. This film diminishes inthickness in the direction of projection of the jets, the jets exertinga force F_(j) on the article tending to displace the article to theright as in FIG. 1. The force F_(j) is balanced by the weight F_(A) ofthe article 22 and by the wedge force F_(w) due to the increasedpressure created in the gap g as the article 22 tends to be displaced inthe direction of projection of the jets. The weight supported is, ofcourse, balanced by the vertical components F_(s) of the wedge force andhence the article 22 may be held in stable equilibrium by the jet andthe necessity for overt guiding beyond that attributable to the wedgephenomenon is redundant.

It is desirable that nozzles 28 and 30 exert a longitudinal forcecomponent on the article due to the increased loading capability withsuch an orientation. In addition, the longitudinal force components ofthe jets will exert an end force on the rear surface of the articlethereby aiding in the propulsion thereof. Also the angled orientationwill assist generally in cleaning the support surfaces of debris andother foreign particles. In addition, the high velocity of the uncoveredjet is safely dissipated in conjunction with the so called "Coanda"effect of the free flow of the jet in close proximity to the tracksurface.

At the optimum design pressure the article 22 will be held inequilibrium slightly above the track and possibly slightly to one sideof the longitudinal center-line. This equilibrium or stability conditionis inherent to this fluid film support system. The jets exiting from thenozzles 30 fan out more or less symmetrically about their center-linesand within the trough configuration of the track in a typical free jetflow pattern to provide the greatest amount of fluid for levitation andguiding. The high velocity, possibly but not necessarily sonic, of theangled jets through interaction with the proximity of the supportsurface is transformed by an apparent free jet phenomena into a lowervelocity high pressure fluid flow propagation over the curved supportsurface in a manner which resembles an air bearing gas film support,because in so doing, the flexible outer covering of the support memberinteracts with the fluid flow of the jet similar to the musical reed ofa saxophone or clarinet instrument in which air is forced between thereed and the support surface in a wedge flow, to produce or create ahigh frequency vibration in the flexible member. This little knownsegment of gas bearing technology (sometimes described as "ultrasoniclubrication" or "High Frequency Induced Air Film Support") is utilizedthusly to create a pulsation or pumping action in the fluid whichincreases the net positive supporting force of the film as well as toassist in the pressure propagation of the air film in the track-supportinterface. This support film pulsation also assists in the eliminationof edge dragging or contact of the support covering with the track. Inthis instance as the film pressure profile between the support surfacesdiminishes towards the track edges, the loading profile on the articleis also made to diminish by virtue of the internal resilient materialtension stresses. In addition, the high frequency pumping action of thevibrating support member covering provides an in-and-out oscillation ofthe film at the support edge to reduce chance of edge drag, andeffectively provide a dynamic film or "moving in-and-out slug of fluid"seal, to reduce air escape and thus minimize air consumption.

The air mass flow of nozzles 28 will of course provide supporting forcesby impact or impingement on the support member covering although theseforces will probably be less than those of the film wedge for theinstant the jet exists prior to transition by free jet into a pressurefilm.

As indicated above, the theoretical considerations respecting thesupport phenomena lead one into gas bearing technology, especially inview of the small gap g, between the article being supported and thesupport surface. In view of the configuration utilized in this supportsystem it would initially appear that the configuration could bedescribed as an "externally pressurized gas bearing" although furtherobservations indicate that the principles of operation of a "squeezefilm gas bearing" may also apply. In a squeeze-film bearing one of thesurfaces is separated by a gas film when vibrated in a direction normalto its plane; the vibration process generates in the gas film asymmetricpressure pulses which, when averaged in time, transmit a new positiveforce tending to keep the surfaces separated. Such vibrations, even atan audible frequency have been observed in prototype configurations(about 2.2 Khz).

Insofar as the externally pressurized technology is concerned it isbelieved that the present configuration may be likened to a thrust orslider bearing wherein the gas is first squeezed and then allowed toexpand with the inlet film thickness being greater than the outlet filmthickness. This change in thickness may take the form of a wedge havingits thickness diminishing in the direction of fluid flow, as in thepresent configuration.

Turning now to the present invention, in one embodiment the use of theabove-described system for the support and conveying of pallets or skidsnecessitates the provision of a satisfactory interface between the loadand its support. That interface is the pallet, or a simple plate, andthe portion of the pallet which will be carried in the conveyor troughs.The pallet per se may take any shape or form as long as sufficientstrength exists to carry the load between the supports. Many of thecurrently available pallets may be utilized. In most instances, thepallet will rest on a pair of support members, one for each longitudinaledge, each support member in turn resting or being supported and guidedin a respective conveyor trough. In order to simplify the description,the conveyor trough and the support member will hereinafter be referredto as the "track" and "shoe" respectively.

The original air conveyor concept as described in Canadian Pat. No.950,853 was developed for the conveying of rolls of toilet tissue orpaper towelling. While such rolls will support a considerable load inradial compression they would not be satisfactory from a long termstandpoint as shoes for a pallet conveying system. On the other hand,the resiliency and stress forces under load deformation exhibited bysuch rolls enhanced by reason of a creping process of the web, aredesirable characteristics for a shoe. Hence a shoe exhibiting the loaddeforming resiliency characteristics of a roll of wound paper and havingan outer resilient hermetically sealed covering of a tough durable andwearable material is seen to be a desirable and acceptableconfiguration. Such a material should be capable of vibrating somewhatunder the influence of the air jets to promote the "squeeze film"phenomenon.

FIG. 2 shows an end view of a track 40 which carries a shoe 42supporting a pallet 44 under load with a fluid pressure profile 40a(FIG. 7). It is seen that the lower surface portion 46 of the shoe hasbeen deformed to where it essentially corresponds in curvature to thetrack surface 48. It is also seen that the upper surface portion 50 ofthe shoe is essentially flat. The surfaces 46 and 50 are connected bycurved surface portions 52.

In order to create the most effective support it is desirable that thelower shoe portion 46 be stressed over the inner resilient portions ofthe shoe and core and be free to vibrate as well as to essentiallycorrespond in curvature to the support surface 48. This will naturallyoccur under load, but it should also occur, although to a lesser extent,under no-load conditions. Accordingly, when there is no load imposed onthe system the lower surface portion 46 should not differ appreciably incurvature from the track surface 48 except for any track irregularities.This suggests an outer stressed peripheral covering for the shoe as seenin FIG. 3 wherein the lower surface portion 46 has a smaller radius ofcurvature than the upper surface portion 50 although the upper surfaceportion is no longer essentially flat as when under load.

If the shoe 42 were to only utilize a wound paper web or sheet in a rollit would be necessary to deform the roll to the cross-sectionalconfiguration shown in FIG. 3. It would be very difficult to maintainthis configuration when in the noload condition or when the load isoccasionally placed on a flat surface. To protect the web and itsdesirable stress properties, the wound web is encased in a thin buttough sheath of a resilient, semi-rigid yet deformable material whichexhibits the desired properties of wear, toughness, economy,impermeability and stiffness and which further aids in producingvibrations created by the air flow from the jets. Materials such asultra-high density (or cross-link) polyethylene, nylon,polyvinylchloride, polytetrafluorethylene and ABS are satisfactory. Evenmetal foils can be used but with less durability where random impacts,as from handling, may occur. The sheath or cover may be reinforced byvarious means, and maybe moulded, extruded or formed to the approximatedesired cross-section and length by standard rotational, blow, orcompression molding techniques as long as some provision for additionaldeformation or stressing under load is made, especially in the method ofsealing the ends of the sheath.

FIGS. 4 and 4a show perspective views of a suitable sheath 54 moldedfrom one of the acceptable materials mentioned above. The length of thesheath corresponds to the length of the pallet to be supported therebyand to the peripheral shape as seen in FIG. 3. Since the entire supportmember should be hermetically sealed, the sheath may be moulded withfront and rear end caps, FIG. 4 showing the front cap 56 only. Front cap56 may include a truncated cone end face 58, a first peripheral ledgeportion 60 and a second inwardly sloping ledge portion 62. There is astep 64 joining ledge portion 60 to the outer surface of the sheath, thestep 64 having a height approximately equal to small debris thicknessencountered on the track. End cap 56 may be removed from sheath 54 bycutting along the line of juncture between step 64 and ledge portion 60to expose the interior of the sheath. Once exposed, a paper roll may bedeformed to a cross-section corresponding to the interior cross-sectionand inserted into the interior. The severed end cap 56 may then be slidinto the interior as well so that ledge portion 62 only is exposed. Theend cap 56 may be sealed to the sheath 54 in any known manner as bybonding, welding or heat sealing. This is seen in FIG. 4a. FIG. 5 showsa cross-section of the completed shoe, including the outer cover orsheath 54, the inner generally coaxial core 66 and, between the core andthe cover, the filler material 68 in the form of a prestressed websubstantally filling the cavity formed between the cover and the core.

The desirability of a resilient yet semi-rigid core is illustrated inFIGS. 6A, 6B, and 6C which illustrate cross-sections of three actualtest samples. Each sample was crosshatched to illustrate the lines andzones of stress and deformation. In FIG. 6A the core is a standardpaperboard core as found in a roll of consumer tissue product. Underload the deformation is uniform although the core has collapsed upwardsdue to the influence of the track curvature. There is a degree ofsymmetry to the deformation and it is seen that restorative forces willbe exerted in the vicinity of the deformed core edges when the load isremoved. The shoe is firm with good springing and dampingcharacteristics.

In FIG. 6B there is no core at all and it is seen that deformation israndom with no lateral stability. This shoe was floppy and completelyunsatisfactory.

In FIG. 6C the core was internally reinforced with a circular springmaterial. There was very little deformation and the shoe exhibitedconsiderably increased spring stiffness and changed dampingcharacteristics. On the basis of test results and observations the besteffects are achieved with a simple cardboard core which exhibitsconsiderable transverse strength when deformed, although under somecircumstances reinforcement may be desirable if special characteristicsof the shoe are desired. In special cases the shoe may be modified byincluding an insert such as a tube containing shock absorbing fluid orcoolant with passage to an end cap reservoir. The fluid would operatethrough high friction or pressure loss orifices or check valve typeorifices to assist circulation and to absorb shocks. Certain types ofpressurized foam or other resilient material may be considered as longas they meet the above-mentioned general requirements.

To summarize to this point the present invention, in one embodiment,relates to a shoe for use in a track as part of an air conveyor ormaterials handling system, the shoe being intended to act as a supportmember for a pallet, skid or flat plate. The shoe, as seen in FIG. 5,comprises an outer cover of a resilient, strong, semi-rigid materialhaving end caps and being capable of vertical deformation and vibration,a core of deformable material which is flexible when deformed in thenarrow or vertical direction and is yet relatively stiff in the wide orhorizontal direction and a filler material which can be pretensioned toprovide a flexible yet resilient weight carrying component capable ofrecovery upon removal of a load from the shoe and capable of allowingthe cover to be vibrated at high frequencies. One particularconfiguration of shoe which is very acceptable comprises a thin outercover or sheath of very tough, slippery and resilient polyethylene, anannular core of paper-board defining an annular cavity between itselfand the cover, and a web of one or two ply creped consumer paper productwound on the core under tension and substantially filling the cavity.The core and wound paper web may be produced as a separate entity andthen positioned within the cover which is subsequently hermeticallysealed via the end cap(s). The shoes contain fastening devices, such asmoulded-in nuts which would facilitate the attachment to plates orpallets to form a skid structure without any loose pieces.

Some words on the wound web are also thought necessary. In order toachieve desirable resiliency characteristics the web should be crepedfrom the paper machine Yankee roll during formation in order to achievea degree of extendable prestressing or spring action of the individualcellulose fibres comprising the web. There should also be controlledtension imparted to the web and the elastic (creped) fibers as it iswound on the core. While mention has been made of a consumer productroll as exhibiting the desired characteristics, it should be understoodthat each roll would extend the full length of the shoe, normallywithout interruption, and that there would be no longitudinalperforations or any other discontinuities in the web, unless exceptionalflexibility were desirable, or special resonant vibration frequencieswere being sought.

FIG. 7 illustrates a force diagram for a loaded shoe, the shoe beingconstructed as described hereinabove. The shoe rests in a track 40 andreceives a load on a flat pallet 44. The load forces are designatedF_(L) and the track reaction forces are F_(T). With the load in placethe wound layers of paper will be placed in compression in the zonesabove the core, in tension below the core 66 and in tension in thecorner zones C which when deformed provide a somewhat structure armeffect. FIG. 7 also shows a fluid pressure profile 40a illustrating thatsupporting pressure is provided across the majority of track 40.

FIG. 8 illustrates an embodiment which enhances the force picture ofFIG. 7, the core 66 having, along the two outer edges thereof,compression arms 70 pivotally connected thereto, the arms havinglongitudinally extending members connected thereto so as to prestressthe wound web at the upper corners of the shoe. Such prestressing andthe additional internal loading achieved under load aids the shoe'stensioned lower portion while providing certain friction between thewound webs and fibres to provide a shock absorber effect.

In FIG. 9 the same effect as that achieved in FIG. 8 is achieved with anoversized reinforcing arch 72 positioned within the core 66. The arch 72is prestressed so as to exert the desired outward forces toward thezones C of FIG. 8.

In FIG. 10 use is made of a corrugated web 76, which reducessubstantially the amount of fiber used in the shoe, surrounded by acompliant cover 74, there being a reinforcing arch 78 positionedcentrally of the shoe.

FIGS. 11 and 12 show basically mechanical shoes which utilize thestiffness of certain covering materials to deform the curvature under"arch compression" to achieve the desired prestressed resiliency of theouter cover without utilizing the central core and wound web. In FIG. 11a tension cable 80 is strung between opposite sides of the cover 54tending to squeeze the sides together so that when a load is applied theinward forces exerted by the load and the cable will force the lowerportion of the cover to extend downwardly into conformance with thetrack surface. It is envisaged that cables might be spaced apart atintervals of say 6 inches over the length of the shoe. FIG. 11 alsoshows a tube or filler piece 82 which could apply additional tension tothe cable and increase the tension even more upon load application.

The principle of FIG. 11 is achieved in the embodiment of FIG. 12 byutilizing a helical tension spring 84 connected at each end to a lug,such as an eye-bolt 86, fixed to the cover wall.

It should be noted that while a filler material made of wound paper hasbeen suggested as being acceptable for shoes in accordance with thepresent invention, it is conceivable that other filler materialsexhibiting similar properties may also be effective. With reference toFIGS. 5 and 18 the filler material 68 could be a continuous web ofcorrugated paper board wound on the core 66 under tension. The fillermaterial can also be a continuous web of extensible plastic film woundon the core 66. Furthermore, the filler material could be a formablemonocellular plastic material which may be expandable to fill the cavitybetween the core 66 and the cover 54. Such materials are adequate, aslong as they provide the desirable support flexibility, frequencyresponse and dampening characteristics as required for the vibration ofthe cover in conjunction with the jet flows.

It has also been determined that the flexible nature of the shoe andsupport surface within limits greatly assists the ability of the supportto accomodate certain track irregularities such as found with ordinarymanufacturing or extrusion tolerances of standard pipe or relativelyabrupt changes in track such as occur at track crossings or gaps. Thecompliant support surface also greatly improves the air filmdistribution between the track and the shoe for superior load carryingand power efficiencies.

The use of a linear motor coil embedded in the track or used as part ofthe track is very much enhanced in its thrust advantages when operatedwith the small air film gap of the support and track combination. Inthis instance, as in FIG. 18 secondary means 136 such as coils, loops orseries of plates required to react with the primary linear motorcomponent 138 in the track, are embedded or contained within the shoesin a manner so as not to greatly reduce the support action with thetrack. The vibration of the covering may be enhanced by the inherentvibrations of electro-magnetic forces of the linear motor. Indeedmechanical or electrical excitation to provide desirable supportvibrations could be generated with the support system described.

It is also quite possible to include a fluid enclosed bladder 140 withoptional orifice restrictions between adjacent longitudinal sections,within the central core, to provide additional damping of shocks orunwanted vibrations as may be experienced or to absorb certain heatproduction such as may be encountered with linear motor reactions.

Turning now to FIGS. 13 to 15 a modular mouldable pallet incorporatingshoes of the present invention is illustrated. Each module 88 includes aribbed upper support surface 90 and a pair of shoes 92 extending alongthe length of the module and depending downwardly from the lower surfacethereof. In keeping with the required properties of the outer shoe coverthe entire pallet could be moulded from the same material. As shown inFIG. 15 each shoe would have a forwardly projecting cap 94 receivable ina corresponding recess 96 of another shoe on another module. Means couldbe provided for interlocking the modules in such a manner as to achievelimited articulation between adjacent modules to aid in traversing gradechanges in the track. Needless to say the interior of each shoe 92 wouldcontain a paper roll or other filler material in order to achieve thedesired cushioning vibrating and support properties. Mechanical tie rodsor strapping may be incorporated to further consolidate the modules.

FIGS. 16, 16a and 17 relate to a somewhat different configuration of thepresent invention, in both the track and the support. This is thesystem, mentioned earlier, wherein the load is supported on a belt whichcan be constructed in a manner similar to the first embodiment albeitwith dimensional differences which are relevant to a belt situation.

As seen in FIG. 16, the belt 98 has a lower surface 100 which isessentially complementary with the upper surface 102 of the track 104,the track being similar to the track 40 of FIGS. 2 and 3. FIG. 16a showshow the belt can be formed, it being seen that the belt is firstprovided with an inner core 106 of deformable metal sheets, wire loopsor thin wire mesh, an outer skin 108 of a flexible, deformable,semi-rigid material and between the inner core 106 and the outer skin108 a flexible, deformable filler material 110. As seen in dotted linesin FIG. 16a the belt is initially formed with a circular cross-sectionand that it is steadily deformed through application of a downward force(arrow) until a lower surface 100 is brought into conformance with thetrack upper surface and an upper surface 112 is forced against the lowerportion defining the lower surface 100. The result is the belt shown inFIG. 16, the belt having a concave upper surface 112 that can receive aload 114 such as wood chips. The materials used in the belt contributeto provide performance similar to the pallet system. It should bepointed out that the wire mesh core will hold the belt in its deformedshape and in turn will tend to tension or prestress the outer skin asrequired.

FIG. 17 shows only one example of a conveyor system utilizing a beltsupport formed in conformance with the present invention. Therein, apair of side-by-side conveyor air tubes 134 are each provided withplenum means and air nozzles such that each can be considered to be atrack having the same properties and function as the track 40 of FIGS. 2and 3 with the exception that the track is enclosed rather than open.The air tubes extended from a loading point 116 to a drop-off or dumppoint 118. Spaced outwardly from each end of the tube is a driveassembly 120 including a motor 122, a barrel-shaped drive pulley 124 andmeans such as drive belt 126 connecting the motor to the pulley. Anendless belt 130, formed in a manner as shown in FIGS. 16 and 16a islocated in the air tubes (tracks) so as to support material on theconcave upper surface thereof. The belt is also entrained about thedrive pulleys 124, the barrel-shape thereof conforming to the concaveupper surface of the belt. Since the pulleys 124 have a generallyvertical axis of rotation the act of entraining the belt therearoundwill force the belt to twist through 90° at 4 zones 132. When thecommodity carried by the belt is a loose material such as wood chips,the twisting action can also serve as the means for dumping thecommodity from the belt. Thus in FIG. 17 the dump point 118 wouldessentially correspond with the twist zone 132. Needless to say theloading zone 116 would be positioned downstream of a twist zone topreclude any premature dumping of the commodity.

The belt conveyor system, can be modified in many ways. For example thereturn belt could also carry a commodity and the return belt need notparallel the first belt. Also if the pulleys 124 had their rotationalaxis horizonal the belt 130 could return on top of the air tube carryingthe loaded belt, the upper portion of the air tube carrying a lowpressure air plenum and nozzles to support the returning belt portionand thereby prevent damage thereto. Furthermore drive for the conveyorcould take the form of an electromagnetic device such as a linearinduction motor wherein the primary coils 134 are positioned in thetrack (FIG. 16) so as to interact with the metal core in the belt whichthen acts as the secondary. This configuration is made possible by thesmall gap between the belt and the track achieved during operation.

It is understood that deviations can be effected in the present inventinby people skilled in the art and the above description is not intendedto cover each and every such possibility. The scope of protectionafforded the present invention should be determined from the appendedclaims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A load supporting meansfor positioning between a load and a load supporting surface, said meansbeing capable of supporting said load and of substantially isolatingsaid load from forces influencing the position of said surface, saidmeans comprising: a generally tubular outer member formed of a resilientpartly deformable material capable of deformation under load and atleast partial recovery under load removal; an annular deformable coreextending generally axially within said outer member, creating anannular cavity between said core and said outer member; a resilientdeformable filler material substantially filling said cavity and beingcapable of deformation under load and at least partial recovery underload removal, said filler material and said outer member beingsufficiently flexible so that at least said outer member can vibrateunder the influence of high velocity fluids exitting from nozzles insaid surface; and including an axially extending, laterally flexible,reinforcing arch member positioned within said core and exerting lateralforces against the wall of said core under loading to assist in stressdistribution within said filler material.
 2. A load supporting means forpositioning between a load and a load supporting surface, said meansbeing capable of supporting said load and of substantially isolatingsaid load from forces influencing the position of said surface, saidmeans comprising: a generally tubular outer member formed of a resilientpartly deformable material capable of deformation under load and atleast partial recovery under load removal; an annular deformable coreextending generally axially within said outer member, creating anannular cavity between said core and said outer member; a resilientdeformable filler material substantially filling said cavity and beingcapable of deformation under load and at least partial recovery underload removal, said filler material and said outer member beingsufficiently flexible so that at least said outer member can vibrateunder the influence of high velocity fluids exitting from nozzles insaid surface; and compression arm means pivotally mounted to theexterior of said core, extending laterally of said core and additionallyprestressing said filler material.
 3. A load supporting means for apallet or skid, comprising: a generally tubular cover member formed of aresilient partly deformable material capable of deformation under loadand at least partial recovery under load removal; a core extendinggenerally axially in said member and creating an annular cavity withinsaid member, said core being formed of a flexible, resilient deformablematerial; a resilient, extensible and compressible filler materialsubstantially filling said cavity, said filler material being capable ofdeformation under load and recovery under load removal, said fillermaterial and said outer member being sufficiently flexible that at leastsaid outer member can vibrate under the influence of high velocityfluids exitting from nozzles in a support surface which can receive saidload supporting means; and wherein said tubular core material and saidfiller material include a series of coil loops, plates, permanentmagnets, or magnetic materials for interaction with an electromagneticpropulsion device within close proximity to a support track for saidload supporting means.
 4. A pallet or skid comprising a load supportingplatform and platform support means attached to a lower surface of saidplatform, said support means including a generally tubular outer memberformed of a resilient, partially deformable material, a core extendinggenerally axially of said member creating an annular cavity within saidmember, said core being formed of a flexible resilient partiallydeformable material, and an extensible and compressible filler materialsubstantially filling said cavity, said support means being capable ofcontrolled deformation under load and recovery upon load removal.
 5. Theinvention of claim 4 wherein said filler material comprises a continuousweb of high bulk paper wound on said core under tension.
 6. Theinvention of claim 4 wherein said filler material comprises a continuousweb of extensible plastic film wound on said core under tension.
 7. Theinvention of claim 4 wherein said filler material comprises amonocellular plastics material which is expanded within said cavity. 8.The invention of claim 4 wherein said filler material is a continuousweb of corrugated paper board wound on said core under tension.
 9. Theinvention of claim 4 wherein said tubular cover member is formed withdeformable end caps which if cut off can be resealed to said member toprovide a hermetically sealed support following insertion of said coreand filler material.
 10. The invention of claim 4 wherein said core isprovided with a flexible tube or bladder sealed and filled with fluid toprovide additional shock absorption, load carrying capacity andtemperature control.
 11. The invention of claim 4 wherein tubular covermaterial and said filler material includes a series of coil loops orplates for interaction with an electromagnetic propulsion device withinclose proximity to a support track for said load supporting means.
 12. Amodular pallet comprising a plurality of longitudinally interengagablepallet modules according to claim 4, each said pallet module having asupport means adjacent each longitudinal edge with each tubular covermember thereof having a forward projection and a rear recess whereby theforward projections of one such module are receivable in thecorresponding rear recesses of another such module, each module beingprovided with means for interlocking adjacent modules together.
 13. Themodular pallet of claim 12 wherein said platform and each said tubularmember thereof are integrably moldable as a single unit.
 14. The modularpallet of claim 12 wherein said platform is internally fitted with aseries of coils, plates or magnets which interact with anelectromagnetic propulsion device set between or close to a supporttrack for said pallet.